Reference
The Scoville Scale, and How to Get a Real Number
Every Scoville figure you have ever read came out of one of two tests that have almost nothing in common. One is five people sipping sugar water in 1912. The other is a machine counting molecules. Both report their answer in the same unit, which is how a scale named after a pharmacist's taste panel ended up carrying numbers nobody tasted.
Where the unit comes from
Wilbur Scoville was a pharmacist. In 1912 he ground peppers, steeped them in alcohol, and diluted the extract with sugar water until a panel of tasters stopped feeling anything. However many dilutions that took became the pepper's rating. The method ran essentially unchallenged for most of the twentieth century, which is the only reason we still measure heat in units named after him.
Its weakness sits right in the middle of it. Tasters differ, tongues adapt, and the same person will not give you the same answer on a Tuesday that they gave you on a Monday. A Scoville figure from a panel is a committee decision wearing a lab coat.
What the machine does instead
High-performance liquid chromatography skips the tasting entirely. A lab grinds the sample down to something uniform, pulls the capsaicinoids out of the plant tissue with a solvent, and pushes that extract through a pressurised column that separates the mixture into its parts. The instrument then picks out the three capsaicinoids that do most of the work, capsaicin, dihydrocapsaicin and nordihydrocapsaicin, and measures how much of each is there. Those three do not burn equally, so each gets weighted before the totals are converted into Scoville units and added up.
The industry writes this down as ASTA Method 21.3, Pungency of Capsicums and Their Oleoresins, published by the American Spice Trade Association. Any lab that will quote you a real number is running that method, and a good one runs duplicates and blind check samples alongside your pods so it can prove the instrument was honest that week.
Where we stand on all this
We do not send anything to a lab. Every heat figure on this site comes from published work, mostly the ranges recorded in WikiPepper , and we would rather say that plainly than dress up somebody else's figure as our own measurement.
We are not heat queens. A number carried out to three digits matters far less to us than whether the pod tastes like anything, and we will take a Monkey Face that bites and tastes of fruit over a bitter superhot bred to win an argument. Treat every published range, ours included, as caveat emptor. It tells you roughly what to expect. It does not tell you what your pod will do in your dirt, in your summer, picked on your schedule.
We do eat them. Everything we grow out gets sampled at some point, mostly out of curiosity about what we have actually got. That is tasting, not measuring, and we are not going to print a number off the back of it.
If you want your own pods tested
Almost nobody writes this part down, so here it is. Southwest Bio-Labs in Las Cruces, New Mexico runs Scoville pungency by HPLC under ASTA 21.3, and has been testing chile products since 1996. They take samples by mail.
Ship to: Chile Lab, Southwest Bio-Labs, 401 N. 17th Street, Suite 11, Las Cruces, NM 88005
Phone: 575-524-8917
Sample receiving: Monday to Friday, 8:00 AM to 3:30 PM
Website: scovilleheatlab.com
Download their submission form, fill it in, and put it in the box with the pods. The form has a tick box that asks whether you want fresh pods reported on a dry matter basis; leave it blank and they report the pods in whatever state they arrived in. They publish no prices, so ring them before you ship anything and ask what the analysis costs and how much material they want for the form you are sending.
One warning about the lists you will find elsewhere. An old New Mexico State University bulletin named three labs for this work, and pepper sites have been copying it ever since. Of the other two, Industrial Laboratories no longer mentions capsaicin or chile testing anywhere on its site, and hauserchemical.com does not resolve at all. Southwest Bio-Labs is the one still advertising the test. Do not find that out by posting pods to a dead address.
Why a plant tag is not a measurement
A processor selling paprika by the tonne tests every lot, because buyers write the figure into the contract. Nobody tests a home variety that way. When a seed packet or a nursery lists 50,000 to 100,000 SHU, it is repeating a published range from somebody else's test, sometimes an old one, usually from a plant grown nowhere near you.
Heat moves with the plant. Sun, water, stress and ripeness all push the number around, and two pods off one bush can land some way apart. The range on a tag, ours included, is a fair estimate of the variety. It is not a claim about the pod in your hand. If you want to know what your plant did this year, the only honest route is to send some of it away and have it counted.
Questions people ask
Lab address, phone, receiving hours and method read off Southwest Bio-Labs' own site and 2026 submission form, September 2026. They publish no prices, so this page quotes none. Labs change their terms without updating every page they own, so call first.